--  @testpoint:opengauss关键字after(非保留)，作为函数名
--关键字不带引号-成功
drop function if exists after;
create function after(i integer)
returns integer
as $$
begin
    return i+1;
end;
$$ language plpgsql;
/
--清理环境
drop function after;

--关键字带双引号-成功
drop function if exists "after";
create function "after"(i integer)
returns integer
as $$
begin
    return i+1;
end;
$$ language plpgsql;
/
--清理环境
drop function "after";

--关键字带单引号-合理报错
drop function if exists 'after';
create function 'after'(i integer)
returns integer
as $$
begin
    return i+1;
end;
$$ language plpgsql;
/

--关键字带反引号-合理报错
drop function if exists `after`;
create function `after`(i integer)
returns integer
as $$
begin
    return i+1;
end;
$$ language plpgsql;
/